A common way to mount solar panels on a structure is by using mounting rails. The structure can be a steel frame which stands alone on posts, or the structure can be the roof of a building, the wall of a building, or the roof or walls of mobile structures such as RVs or vehicles. The example of solar panels which are mounted on the roof of a structure will be used for convenience, but is not meant to limit the claimed technology. Solar panels are typically rectangular and are mounted on mounting rails. The mounting rails are generally not perfectly parallel with the edge of the roof line. Some mounting rails have waves and curves and are not even close to being parallel with any straight line on the roof. Ideally, the rails would be perfectly parallel with a straight line of the roof, such as the bottom edge of the roof, the top edge of the roof, or the side of the roof. In reality, the rails are not perfectly parallel with the roof edge and they are not even parallel with each other.
The problem is when an array of rectangular solar panels is placed edge to edge on a roof; if they are not perfectly parallel with part of the roof, such as the lower edge of the roof, it is very obvious that they are not parallel, and the solar panel looks crooked.
The goal is to mount an array of solar panels so that all the bottom edges of the solar panels are aligned, or if they are not aligned, so that the bottom edge of the array of solar panels is parallel with the bottom edge of the roof or some other visible part of the roof.
What is needed is a tool which helps the installer of solar panels make the solar panel array parallel, in that the bottom edge of the solar panels can be controlled so that the entire array looks straight.